-The Louisiana Purchase never happened, instead it's obtained (along with Florida) in a war with Spain from 1825-7
-Mississippi Territory does not incorporate the Gulf coastline, and so instead of being divided north-south (to give both states access to the Gulf), it's divided east-west (to give both states access to the Mississippi)
-Without the War of 1812, the Maine statehood movement is much weaker, and after a certain point it falls into a stiff decline (OTL Democratic Maine being part of OTL Whiggish Massachusetts means Massachusetts is somewhat of a swing state, and this gives Maine a strong position of influence when Populists come to power in the state)
-Without the Louisiana Purchase, there's a lot more southern migration into the Midwest, and it's enough to tip Illinois into ratifying a slave state constitution which gets approved by Congress after a brief sectional crisis, and as a result its boundary does not get revised northwards and it lacks Chicago
-Michigan gets the Toledo Strip, and as a result it doesn't get the Upper Peninsula
-When the US conquers Spanish Louisiana, the OTL Louisiana state has enough population to be annexed immediately
-Many of the southerners who went into Texas in OTL instead go into Missouri. With Illinois a slave state, they're able to open slave plantations on the Mississippi shore, and Missouri is far more securely a slave state
-Missouri is smaller (boundary at the Osage) due to a stronger North during the later Missouri crisis though
-As part of Indian Removal, the Five Civilized Tribes are instead deported to Kansas due to the government intending on opening OTL Oklahoma to slave stater migration, but a lot of them find it too icy and the OTL attempts to migrate to Texas (here, Spanish) succeed much more
-An OTL proposal to turn most of southern Minnesota (in a time where it was thought too cold for white people) into an Indian Territory to deport Midwestern tribes gets through with the Midwest more settled and Minnesota less than OTL
-Wisconsin initially wants to get the remainder of the Northwest Territory, but it gets blocked from annexing the St. Croix Valley and the Upper Peninsula, which instead goes to a separate state, called Ontonagon as was an OTL proposal (Congress refused to let it name itself Superior)
-Needing to shore up the South's position in the Senate results in Florida (incl. the bits annexed by Alabama, Mississippi, and Louisiana) divided into two
-With a much later acquisition of Louisiana, Britain is able to get firm control over the Oregon Territory, the US buys the Olympic Peninsula and the right to build roads to and from it for an ample sum later on
-Iowa gets a very different shape because the North, wanting to pack in more free states, secures for it a smaller western boundary extending Missouri's and, as compensation, gives it a bit of the North-West Indian Territory stretching to OTL Minneapolis as was an OTL proposal, then stretched further to construct railroads through it
-Pembina Territory gets opened up in order to open up a path to a northern transcontinental railroad, and also to satisfy land hunger for the South-West Indian Territory, but it gets settled very slowly
-When the west got opened up beyond Missouri and Iowa to make room for the railroad, South-West Indian Territory was abruptly reduced to OTL Colorado, and with a lot of Native Americans wholly unwilling to move to those semi-arid areas, there's instead a lot of migration to Spanish Texas, but with most made the large Nebraska Territory spanning Kansas but excluding most of the Dakotas, Montana, and Wyoming (as with some OTL Kansas-Nebraska proposals)
-When Missourian slaveowners forcibly enter adjacent bits of Nebraska Territory to secure it for slavery despite the Missouri Compromise, they eventually succeed and Nebraska's divided into the territories of Kansas and Platte, along the Platte River
-Kansas ends up dominated by slaveowners who force a Dred Scott-style decision by ratifying a slave code, and this results in free soilers sweeping in
-Slavery tensions spark a civil war after the disputed 1868 election, goes much worse for the North but it wins by 1876
-In the interim, to prevent a pro-compromise candidate from winning the coming election, the North admits a number of states (not recognized by southern government)
-Platte gets chopped up, with only the eastern part made a state straight away and the western part lacking enough inhabitants
-Olympia, effectively a city-state centred around the city-state of the much larger Port Townsend (the only American port on the Pacific), gets admission
-West Virginia is much smaller because the James River and Kanawha Canal gets constructed and turns the Kanawha Valley into a slaveowning region
-East Tennessee's statehood movement goes off and succeeds, with the name of its 1780s attempt
-Maine's statehood movement makes a return with Massachusetts becoming very much dominant-party to the detriment of its importance, and it gets it
-The western part of Platte Territory except a gold-heavy western part, gets admitted as Cheyenne (a name proposed in OTL for Wyoming), with most settlement being post-war
-The remaining unorganized territory gets large gold strikes near the transcontinental railroad, results in settlement and rapid statehood as a state named after George Washington (this clunky name was proposed for OTL Washington by Stephen Douglas)
-DC gets statehood this early because the Chesapeake and Ohio Canal gets built and the Second Bank of the United States is headquartered there, giving it a lot more development a lot earlier, and after it gets redeveloped post-war, it finally gets statehood with the name Anacostia (after the river, has been proposed in OTL)
-The Pike's Peak Gold Rush happens considerably later than OTL because California is not part of the US and thus less people going that way, and the state is reserved for Native Americans, but it does eventually occur, and the South-West Indian Territory is forcibly opened up for settlement - the name Tahosa was proposed in OTL
-The remaining land also gets settled, with a small border adjustment giving it control of the whole west bank of the Missouri River because the federal government doesn't want it in the North-West Indian Territory in the name of security (thus why it looks like that), and it gets admitted as the State of Jefferson (a name proposed a few times in OTL)
-The North-West Indian Territory gets a number of other Native American tribes deported there (with a lot of friction between them and the Dakota) as well as a fair number of Metis fleeing the Red River Colony's annexation to Upper Canada, and they're reluctant for statehood because it would mean allowing white settlers, but with the frontier closed everywhere else there's an increasing land hunger for it, and so after some years of close but failed votes for opening it up, they apply for statehood as "Minasota" under a constitution giving them protection and get it, and they're able to manage the subsequent white settlement well

-New York City gets amalgamated early (in 1872) when Queens wasn't a big thing, and so it's a union of Manhattan and Brooklyn, and it eats the Bronx (and into Westchester) and some parts of Queens slowly afterwards
-In contrast, the water controversies between Brooklyn and the rest of Long Island over the late 19th century are won by Brooklyn, and as a result Long Island's development is delayed by a fair bit, with development instead concentrated northward in the Bronx
-In general, the Midwest never turns into the Rust Belt because, first, this is a timeline without World War II and so the US doesn't just sit complacent in its industry's super-confidence, and second, without California and the rest of the west, industry doesn't move stuff like the tech boom instead occurs in the Midwest
-With Chicago being in a separate state from Illinois, the canal to the Mississippi that made it big gets constructed later, and the raising of the city also takes longer. By the time they get accomplished, Chicago gets an impressive boom but it's too late for it to become a grand railway hub, and instead St. Louis remains the US's second city to the modern day
-Cincinnati remains the top ten cities as it was in the 19th century because it becomes a larger railway hub very early, helped by Chicago not getting its shit together until later
-The Erie and Ohio and Miami and Erie Canals get constructed in the 1810s and 20s, helping both Cincinnati and Toledo
-Michigan gets Toledo, and it becomes its great metropolis in place of Detroit - however, it doesn't become the centre of the car industry, and so it gets more modest growth during the car boom but also escapes the urban decay afterwards
-The James River and Kanawha Canal (incl. a portage railroad) gets successfully completed in 1836, giving Richmond a dramatic boom
-Also, without slave plantations expanding with the annexation of Texas, more slaves are used for southern industry, especially Richmond
-Meanwhile Baltimoreans don't decide to construct a railroad to the Midwest (they did so at the ridiculously early date of 1827 in OTL!) in favor of a less impressive canal connecting it to Pennsylvania's canal system, and so Baltimore gradually declines and effectively becomes a suburb of Washington
-The Chesapeake and Ohio Canal gets constructed all the way to Pittsburgh, and this results in Washington DC booming in the antebellum period
-Note that this boom also means it gets statehood much earlier than OTL (with the name for the state coming from a river in the region)
-With the US never expanding to the Pacific (with one exception), the Mississippi is more important and it gets a lot more internal improvements, with knock-off effects across it (most dramatically in New Orleans)
-The Erie Canal's terminus is selected as Black Rock instead of Buffalo, and so Black Rock eats Buffalo instead of the other way around
-The US purchases the Olympic Peninsula in the 1840s along with the right to build roads across British territory to it, and subsequently develops Port Townsend on it into a big city
-Michigan City blooms in size because, in the absence of Chicago (for a while) it is able to make itself the premier port on Lake Michigan till Chicago benefits from being the sole connecting city between east and west for the Constitutionalists in the Civil War, with aggressive competition b/w Chicago and Michigan City for title of largest port afterwards (won by Chicago)
-Instead of Cleveland, Sandusky gets selected as the mouth of the Ohio and Erie Canal, and it gets the subsequent boom
-Due to Mississippi navigational improvements, the Twin Cities are larger, and because Louisiana was acquired in 1827 rather than 1803, land east of the Mississippi was opened before land west of it, and so Saint Paul has a considerable head start against Minneapolis and gets to be larger
-A canal connecting Savannah with the Tennessee River gets built in the 1820s, and Atlanta is founded with its original indigenous name well earlier, and when it ends up a railway hub later in the 19th century, it keeps this name even after people consider it a bit silly
-The Charleston-Louisville-Cincinnati Railroad proposed in 1832 in OTL (by Nullifiers!) gets constructed, and this helps give Charleston, one of the largest ten cities in the US until 1850, keep its position. This has gigantic political effects on South Carolina, including making it a more "normal" southern state, and the industrial projects of people like William Gregg achieve more success
-Also Louisville benefits greatly from the James River and Kanawha Canal trade and a railroad constructed from the Kanawha to it
-In general, the antebellum South sees more (slave-powered) industrialization in the antebellum period than OTL, and this has a host of effects on its urban development, the largest being that Birmingham gets founded (and booms) earlier, and it is named after a different industrial city
-Due to Louisiana being acquired later, East St. Louis booms as an American port, though still overshadowed by St. Louis, and later on suburbanization from St. Louis leads it to expand a great deal
-Independence, Missouri (the name is convergent but I love it so much I'm keeping it) gets to be bigger due to the the transcontinental railroad going through it, and it swallows up much of Kansas City (due to no Platte Purchase, some of Kansas City, Missouri ends up on the Kansas state side)
-Peoria (along the Illinois River) is developed by Illinois into a city, with it lacking Chicago, even though it is overshadowed by the St. Louis metropolitan area
-Wilmington, which was the largest city in NC until the 1898 overthrow of its city government (part of the final closing of Reconstruction) led to its decline, here gets to be NC's largest city
-With Florida under Spanish rule for longer, St. Augustine gets to be somewhat larger upon American rule and, instead of Jacksonville, gets developed into a large-ish city
-Fort Wayne is bigger because it's both on the Wabash and Erie Canal and the terminus of the canal to Michigan City